Confused with batteries in series.

[DimitriP]

Trying to "learn electricity" using a wire and batteries is like trying to "learn surgury" with a butcher knife.

In the next episode:
How can flat batteries still work?

[IanB]

Im still a bit confused guys, I do understand that you have to have a closed loop circuit for electricity in series thats not what Im asking. Its not a basic question i am trying to ask. What i am trying to ask, is why when touching the + to another battery - electricity doesn’t flow?

You are assuming all positive terminals and all negative terminals are equivalent. They are not. You need to label the batteries #1 and #2 (first battery and second battery).

So, you can now label the terminals on the first battery as "Positive#1" and "Negative#1". You can label the other battery with "Positive#2" and "Negative#2".

Now, when you connect Positive#1 and Negative#1 with a wire, electricity can flow out of Positive#1, through the wire, into Negative#1, through the battery, and back to Positive#1. The through the battery bit is important. It is how the electricity gets back to the starting point (what closes the loop).

Draw this with a pencil on your diagram to be sure you understand it.

So let's try the same experiment with the two batteries. Electricity can flow out of Positive#1, through the wire, into Negative#2, through the second battery, out of Positive#2, and...then where? Where has the electricity got to go? There is no wire attached to Positive#2, so there is a dead end. There is no circuit. Therefore no electricity can flow.

Draw this again with your pencil on your drawing. How can you get back to home after you leave the positive terminal of the second battery?

If you want a different way to think about this, think about a motorway with traffic flowing along it. Suppose there is an accident and the carriageway is blocked? All the traffic comes to a standstill because it can't get past. All flow of traffic is stopped. The same is with electricity. If there is no path forward, the flow is blocked and everything comes to a standstill.

Someone earlier mentioned about static electricity with balloons and such. Guess why it is called "static" electricity? Static means stationary, not moving. Same thing. If electricity hasn't got a path to follow, it is stuck and doesn't move.

[drussell]

The key thing to understand is that electronics operate under a restricted subset of physical laws. Clearly you do not need a closed path for electricity to flow: rubbing a balloon on a fur coat will quickly disabuse you of this notion!
However, electronic circuits are somewhat simplified and the above example (where electrons "bunch up" in one place) is not allowed. The simplified laws allow for easier analysis. There are two main simplified models in electronics, called the Lumped Element model and the Transmission Line model. The Lumped Element model is introduced first and is easier to understand. It contains two classes of entities: Elements, such as resistors and capacitors; and Wires. Wires are assumed to be of zero impedance, as if they were perfect conductors. Elements are assumed to be located at a single point in space and only connected to the world through their attached Wires.

When the Lumped Element model is applied to your example of the two batteries, we notice something right away. Since charges are not allowed to bunch up anywhere in the circuit, each electron that wants to leave a battery through its (-) terminal needs to be replaced by another electron entering the battery at its (+) terminal. If there is nothing attached at the other terminal, they cannot move.

Thanks for posting this.  I found it very helpful in connecting some "understanding dots".  It might be a tad off topic or beyond topic regarding the OP's original question but still, it helped generate some insight.  In looking up the definitions of lumped element vs transmission line I found that perhaps the compare and contrast might be better termed lumped element vs distributed element (or distributed system?) but that's maybe a terminology nit.  (And no doubt we take our terminology pretty seriously so I am ready to be stand corrected....)

Ahh, geez, guys, the poor kid was just trying to understand why two unconnected cells/batteries don't short out across thin air.... 

Do we need to get into lumped element vs distributed element analysis in a beginner's thread?   

[greenpossum]

I'm more interested in knowing how the OP's misconception came about. I suspect it's through interpreting very literally the "rule" that current flows from + to -. 

[Brumby]

Im still a bit confused guys .... .... ....
What i am trying to ask, is why when touching the + to another battery - electricity doesn’t flow?

Hi challie2!

When it comes to these very basic questions of understanding, you will gets lots of replies that are accurate - but are not helping you understand.  This is, perhaps, one of the greatest challenges of the newcomer - wading through it all.  (In fact, there's a graphic somewhere which has been used before - I'll dig it up ...)

I suggest you read THIS reply and pay close attention as it is the only one I've read so far that clearly and succinctly makes the point you need to understand....

The + of a battery is only + with respect to, or relative to, its own - end. It is not + or anything with respect to the other battery’s - end.

[Brumby]

Here's the graphic I mentioned....

[Electro Fan]

The key thing to understand is that electronics operate under a restricted subset of physical laws. Clearly you do not need a closed path for electricity to flow: rubbing a balloon on a fur coat will quickly disabuse you of this notion!
However, electronic circuits are somewhat simplified and the above example (where electrons "bunch up" in one place) is not allowed. The simplified laws allow for easier analysis. There are two main simplified models in electronics, called the Lumped Element model and the Transmission Line model. The Lumped Element model is introduced first and is easier to understand. It contains two classes of entities: Elements, such as resistors and capacitors; and Wires. Wires are assumed to be of zero impedance, as if they were perfect conductors. Elements are assumed to be located at a single point in space and only connected to the world through their attached Wires.

When the Lumped Element model is applied to your example of the two batteries, we notice something right away. Since charges are not allowed to bunch up anywhere in the circuit, each electron that wants to leave a battery through its (-) terminal needs to be replaced by another electron entering the battery at its (+) terminal. If there is nothing attached at the other terminal, they cannot move.

Thanks for posting this.  I found it very helpful in connecting some "understanding dots".  It might be a tad off topic or beyond topic regarding the OP's original question but still, it helped generate some insight.  In looking up the definitions of lumped element vs transmission line I found that perhaps the compare and contrast might be better termed lumped element vs distributed element (or distributed system?) but that's maybe a terminology nit.  (And no doubt we take our terminology pretty seriously so I am ready to be stand corrected....)

Ahh, geez, guys, the poor kid was just trying to understand why two unconnected cells/batteries don't short out across thin air.... 

Do we need to get into lumped element vs distributed element analysis in a beginner's thread?   

Point well taken. 

[Electro Fan]

Here's the graphic I mentioned....

challie2, this is great advice.  Give us your next question....

[Jwillis]

I tried to go with as simple an explanation as I could . When you look at a battery . The positive side is not positively charged but has a lower negative potential than the negative side . I used your picture to give an explanation.

Sorry about the lopsided picture.

[ejeffrey]

I'm sorry, but that is absolutely  not true.  It is possible to define, quantify and measure the potential of an isolated object and that measurement is not relative to anything else.  The usual definition of zero potential is when the charges are equal.  Whether current will flow to or from another object is dependent on their relative potential, but there are other effects that only depend on the absolute charge difference.  For example, if you charge up an object to a high enough absolute voltage, it can explode from the electrostatic repulsion of similar charges.  That effect does not depend in any way on the presence or effect of another object or potential.

You are confusing charge with voltage.  Charge causes voltage but they aren't the same thing.  There are no effects whatsoever that depend on absolute voltage.  An object with high net charge will indeed experience repulsion between those charges, independent of the voltage.  I 100% promise you that there is no meaning or measurable effect of absolute voltage. Charges respond to electric fields.  Electric field is the gradient of voltage.  Adding a constant voltage offset doesn't change the gradient, therefore doesn't change the electric field, and has no effect on any measurable force.  You can hide the reference terminal, but you can't eliminate it.

You can measure absolute voltage with one of these. 

https://www.arborsci.com/products/demonstration-electroscope?variant=18112031195209&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=CjwKCAjw2Jb7BRBHEiwAXTR4jfyo1IPxDsruewpqzHqaPzP1LB7kjvYdgtb744xl1Epc9rnExJJBlBoCxeAQAvD_BwE

That measures the charge on the plate, not any "absolute" voltage which again -- is not a real thing.  You can see this by a simple example: take your electroscope and charge up the plate so that the needle moves.  Then attach a battery or power supply to the base plate.  As you adjust that power supply the voltage of the entire system will be shifted relative to the power supply ground but the needle won't move.  That's because the charge on the plate won't change.

[radiolistener]

Its not a basic question i am trying to ask. What i am trying to ask, is why when touching the + to another battery - electricity doesn’t flow?

If you're trying look under the hood, then you're come to AC world. The answer on your question - it flows. When you connect (-) terminal of first battery with (+) terminal of second battery, the electric current is really flows. But it flows for very-very short period of time, so you even cannot notice it. It just stops to flow in a short period of time, because there is no path to flow.

The same thing happens when you connect water pump to a pipe with closed output on the other pipe end. At the first moment water flows from pump into pipe. But since there is no output from pipe, the pressure quickly raise and this pressure produces a counteracting to the pump.

The same thing happens in the wire with electron gas. When you connect wire to (+) terminal of the second battery, electron gas flows from the first battery to the second battery. But since there is no output from (-) terminal on the second battery, it leads to higher density of electron gas and it starts to flow back to the first battery. This is known as wave reflection. And this is what is described in Transmission Line theory.

Actually electrons don't sit at the same location, it always move at random direction. But when there is no way to move, it just move back and forth at random directions. And in average there is no movement. These random back and forth movement of electrons is everywhere. It is known as thermal noise. You can hear this electrons movement with amplifier, for example you can listen it with a good radio receiver

[Fixpoint]

@challie2:

When the other guys say you need a "loop" that means you need some sort of CIRCLE (hence "circuit"). If you just connect two batteries like this:

[PLUS1-MINUS1]---[PLUS2-MINUS2]

there is no circle. Yes, there is a *connection* between MINUS1 and PLUS2, but this connection does not form a circle.

Some words specific to batteries: a battery works by means of a chemical reaction that moves electrons from MINUS to PLUS. For this movement, some sort of bridge must be created between the terminals. The electronics do not move within the battery itself from MINUS to PLUS (otherwise, there would be short within the battery and you couldn't use it for anything).

If you create the series connection as above, the terminals of the individual batteries 1 and 2 are not bridged (that means, there is no connection from MINUS1 to PLUS1 and no connection from MINUS2 to PLUS2), so no chemical reaction can take place that moves electrons from MINUS1 to PLUS1 or from MINUS2 to PLUS2. You think that they should move from MINUS1 to PLUS2, but between those terminals, there is no battery, so no chemical reaction can take place to move the electrons.

The only places here where chemical reactions can take place is within battery 1 and battery 2, and those reactions "want" to move electrons from MINUS1 to PLUS1 and from MINUS2 to PLUS2. The series connection above only supports those reactions if the circle is closed, not when it is open.

[radiolistener]

You think that they should move from MINUS1 to PLUS2, but between those terminals, there is no battery, so no chemical reaction can take place to move the electrons.

Actually they always move. And electric current will flows from MINUS1 to PLUS2, but since there is no path to continue flow, it will be reflected back from PLUS2 terminal and flow back to MINUS1.

So, when you attach MINUS1 to PLUS2 you will see electric current something like this:


But the frequency of this bouncing will be very high, because electricity is really fast So your voltmeter cannot measure it, because current drops to zero at very-very short period of time.

If you want to catch such current of open circuit, you can try to use very long coaxial cable with open end. Since wave propagation in coax cable is about 197'863 kilometers per second, you can measure current between battery and cable before pulse reach to the end of cable and returns back to the battery. You will see a short pulse of current when you attach long cable to the battery.

[tooki]

Its not a basic question i am trying to ask. What i am trying to ask, is why when touching the + to another battery - electricity doesn’t flow?

If you're trying look under the hood, then you're come to AC world. The answer on your question - it flows. When you connect (-) terminal of first battery with (+) terminal of second battery, the electric current is really flows. But it flows for very-very short period of time, so you even cannot notice it. It just stops to flow in a short period of time, because there is no path to flow.

The same thing happens when you connect water pump to a pipe with closed output on the other pipe end. At the first moment water flows from pump into pipe. But since there is no output from pipe, the pressure quickly raise and this pressure produces a counteracting to the pump.

The same thing happens in the wire with electron gas. When you connect wire to (+) terminal of the second battery, electron gas flows from the first battery to the second battery. But since there is no output from (-) terminal on the second battery, it leads to higher density of electron gas and it starts to flow back to the first battery. This is known as wave reflection. And this is what is described in Transmission Line theory.

Actually electrons don't sit at the same location, it always move at random direction. But when there is no way to move, it just move back and forth at random directions. And in average there is no movement. These random back and forth movement of electrons is everywhere. It is known as thermal noise. You can hear this electrons movement with amplifier, for example you can listen it with a good radio receiver

You think that they should move from MINUS1 to PLUS2, but between those terminals, there is no battery, so no chemical reaction can take place to move the electrons.

Actually they always move. And electric current will flows from MINUS1 to PLUS2, but since there is no path to continue flow, it will be reflected back from PLUS2 terminal and flow back to MINUS1.

So, when you attach MINUS1 to PLUS2 you will see electric current something like this:


But the frequency of this bouncing will be very high, because electricity is really fast So your voltmeter cannot measure it, because current drops to zero at very-very short period of time.

If you want to catch such current of open circuit, you can try to use very long coaxial cable with open end. Since wave propagation in coax cable is about 197'863 kilometers per second, you can measure current between battery and cable before pulse reach to the end of cable and returns back to the battery. You will see a short pulse of current when you attach long cable to the battery.

All of this is completely unhelpful to furthering the OP's understanding, just potentially adding more confusion.

[tooki]

Voltage really is always relative.  That is not an approximation or simplification is a fundamental fact of nature.

I'm sorry, but that is absolutely  not true.  It is possible to define, quantify and measure the potential of an isolated object and that measurement is not relative to anything else.  The usual definition of zero potential is when the charges are equal.  Whether current will flow to or from another object is dependent on their relative potential, but there are other effects that only depend on the absolute charge difference.  For example, if you charge up an object to a high enough absolute voltage, it can explode from the electrostatic repulsion of similar charges.  That effect does not depend in any way on the presence or effect of another object or potential.

You can measure absolute voltage with one of these. 

https://www.arborsci.com/products/demonstration-electroscope?variant=18112031195209&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=CjwKCAjw2Jb7BRBHEiwAXTR4jfyo1IPxDsruewpqzHqaPzP1LB7kjvYdgtb744xl1Epc9rnExJJBlBoCxeAQAvD_BwE

Again, not helpful to the OP's understanding. And while it may be true (dubious) from a pure physics standpoint that voltage can be absolute, the electronics in question here clearly and unambiguously deals only with current electricity, where voltage is definitely a relative measurement. Bringing electroscopes into the picture for someone who clearly needs to be learning the basics of a multimeter is simply not helpful.

[Brumby]

But this is completely unhelpful to furthering the OP's understanding, just potentially adding more confusion.

I couldn't agree more.

[radiolistener]

But this is completely unhelpful to furthering the OP's understanding, just potentially adding more confusion.

He said that he want to know why there is no current. I think he understand that it needs circuit for current flow, but he want to understand why current is missing when there is circuit break.

[Fixpoint]

He said that he want to know why there is no current. I think he understand that it needs circuit for current, but he want to understand why current is missing when there is break.

that doesn't make any sense. if i have understood that I need a circle, then i don't need to ask why there is no current without a circle. please let us stop this wankery and concentrate on helping the op.

[radiolistener]

that doesn't make any sense. if i have understood that I need a circle, then i don't need to ask why there is no current without a circle. please let us stop this wankery and concentrate on helping the op.

He may know that there is need a closed electrical circuit for a current flow just because someone said that. But it doesn't means that he understand why

Anyway, after so many comments, I think now he should understand it. So, let's wait what he says

[Circlotron]

All of this is completely unhelpful to furthering the OP's understanding, just potentially adding more confusion.

This thread is like when a young child asks where do babies come from and they end up getting a lecture on obstetrics and gynaecology and who knows what else, when they would be satisfied with the answer "mummy's tummy."

[Fixpoint]

in my post above I have tried to make it as simple and concise as possible, but this attempt gets sabotaged basically immediately. I think in this forum there is a lack of rules how to behave in threads like this.

[radiolistener]

in my post above I have tried to make it as simple and concise as possible, but this attempt gets sabotaged basically immediately. I think in this forum there is a lack of rules how to behave in threads like this.

your answer, which you're talking about, is that there is need a closed loop circuit and what it means.

But just look what topic starter wrote before your answer:

Im still a bit confused guys, I do understand that you have to have a closed loop circuit for electricity in series thats not what Im asking. Its not a basic question i am trying to ask. What i am trying to ask, is why when touching the + to another battery - electricity doesn’t flow?

This is pretty obvious, that the topic starter claims that he know, that there is need a closed loop. But he asking why current don't flows.

But after that you're trying to explain that there is need closed loop and what it means.
And you wrote that he don't need answer why:

He said that he want to know why there is no current. I think he understand that it needs circuit for current, but he want to understand why current is missing when there is break.

that doesn't make any sense. if i have understood that I need a circle, then i don't need to ask why there is no current without a circle. please let us stop this wankery and concentrate on helping the op.

As you can see, your answer is not what topic starter asked for.

You're trying to say that the answer on topic starter question "why" doesn't make any sense, because if he know about closed loop, then he "don't need to ask why"...

But topic starter clearly stated that he needs answer "why".
And  he clearly stated that he already knows that there is needs closed loop.

So who attempts to sabotage?

[Ground_Loop]

for the two batteries, connect the other positive to the other negative and you will have a closed loop and current will flow.

[radiolistener]

another example of current flow with no closed loop is a capacitor. There is no connection between capacitor terminals. But if you apply battery to the capacitor, you will see a short pulse of current. After some period of time needed to charge capacitor, current will drops to zero.

The same thing happens when you connect terminals MINUS1 and PLUS2, but since capacitance is much lower, it will happens much-much faster

[bdunham7]

You are confusing charge with voltage. 

No, really, I"m not.  I was only providing a simple explanation that I thought the OP might understand, not a complete grade-school class on electrostatics, but to simply refute your assertion:

1.  Charge is measured in Coulombs. 
2.  Potential, aka voltage,  is defined in terms of the work required (+ or -) to move a unit charge from one state or object to another.  This holds for any type of voltage, whether it be a 9V battery or a balloon.  What I call 'absolute' voltage is the work required to move a unit charge from infinity to the charged object. 
3.  Charge and potential are related to each other and as far as single, isolated objects go, that relationship is called Capacitance.

That measures the charge on the plate, not any "absolute" voltage which again -- is not a real thing.  You can see this by a simple example: take your electroscope and charge up the plate so that the needle moves.  Then attach a battery or power supply to the base plate.  As you adjust that power supply the voltage of the entire system will be shifted relative to the power supply ground but the needle won't move.  That's because the charge on the plate won't change.

I'm assuming your power supply is grounded to earth on the other end.  The balanced-pointer electroscope ideally responds to its own charge and not external electric fields because external fields will act on both sides of the pointer uniformly.  With foil-type indicators your experiment might actually cause some change if the power supply were strong enough.  I don't have any idea what you mean when you say the voltage of the entire system will be shifted--two isolated objects that you define as a 'system' don't have one single potential.  The base plate is insulated from the indicator so no charge is transferred.  The indicator doesn't move because it is responding to its own 'absolute' voltage potential, not any external field.